Estimation of the size of software is an essential part of Software Project Management. It helps the project manager to further predict the effort and time which will be needed to build the project. Various measures are used in project size estimation. Some of these are:

• Lines of Code

• Number of entities in ER diagram

• Total number of processes in detailed data flow diagram

• Function points

Lines of Code (LOC)

As the name suggest, LOC count the total number of lines of source code in a project. The units of LOC are:

• KLOC- Thousand lines of code

• NLOC- Non comment lines of code

• KDSI- Thousands of delivered source instruction

The size is estimated by comparing it with the existing systems of same kind. The experts use it to predict the required size of various components of software and then add them to get the total size.

Advantages:

• Universally accepted and is used in many models like COCOMO.

• Estimation is closer to developer’s perspective.

• Simple to use.

Disadvantages:

a. Difficult to measure LOC in the early stages of a new product.

b. Source instructions vary with coding languages, design methods and with programmer’s ability.

c. No industry standard for measuring LOC.

d. LOC cannot be used for normalizing if platforms and languages are different.

e. The only way to predict LOC for a new app to be developed is through analogy based on similar software application.

f. Programmers may be rewarded for writing more LOC based on a misconception of higher management by thinking that more the LOC, means more the productivity of the programmer